var secondGeDom = document.querySelector('#second_ge');

var itemHeight = 120;
var totalTime = 10;
var curTime = 0;
var timerId = null;

function init() {
  beginTimer();
}

function beginTimer() {
  if (timerId) {
    return;
  }
  timerId = setInterval(() => {
    curTime++;
    if (curTime > totalTime) {
      clearInterval(timerId);
      timerId = null;
      return;
    }
    secondGeDom.top = itemHeight;
  }, 1000);
}

init(); //初始化
